It took me an entire year to work on the optimisation of the project.
Starting from a very careful design of PCB, through design of the case toward the final product.
Then selection of parts suppliers, long search for aluminium case maker, through assembly of cases and electronics,
testing and final optimization. But it was worth it!

Main features and improvements since prototype:

Full Dual Mono architecture 2x8W (2x2.3W operating in pure class A). This is the only solution that allows for proper ground topology when using Phono outputs.

Symmetry across all PCBs along with uncompromised ground paths topology which made possible decreasing the noise and power line hum to inaudible levels.

Improved power supply and added surface mounted high class ceramic capacitors to improve impulse response throughout the entire signal path.

All connectors and relays used in a signal path are duplicated to decrease distortions and improve damping factor.

Before end of the year I decided to take a short break from coding and came
back to my old and the most important hobby - electronics, which I was dealing with already before
I was able to read.;)
In just 8 weeks I have made a design and built from scratch a prototype Hi-End headphone amplifier.
I was starting just from bare materials like wood, aluminium and of course a pile of electronic parts and rolls of wires.
I wanted to check the design and start with production in case parameters are promisingly good.